Vehicle refrigeration system and related methods

ABSTRACT

A vehicle refrigeration system includes a vehicle power device, and a vehicle refrigeration device coupled to the vehicle power device. The vehicle refrigeration device includes an evaporator configured to provide cooling based upon refrigerant fluid, a condenser configured to process the refrigerant fluid downstream from the evaporator, and a compressor configured to operate based upon a combined voltage, and transmit the refrigerant fluid from the evaporator to the condenser.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/013,070 filed Jun. 20, 2018, now U.S. Pat. No. 10,790,681, which is acontinuation-in-part of U.S. patent application Ser. No. 14/807,459filed Jul. 23, 2015, now U.S. Pat. No. 10,106,110, which claims priorityto U.S. Provisional Patent Application Ser. No. 62/028,096, filed Jul.23, 2014, and U.S. Provisional Patent Application Ser. No. 62/126,081filed Feb. 27, 2015 the entire subject matters of which is incorporatedherein by reference in their entirety.

TECHNICAL FIELD

The present invention is directed to a vehicle power system, and moreparticularly, to a vehicle power system for providing power frombatteries to a load and related methods.

BACKGROUND

The electrical requirements for the automotive, truck, boat andrecreational vehicle industry have, with few exceptions, becomestandardized using twelve volt direct current (DC) electrical systemsand using one or more twelve volt batteries wired in parallel forstorage. Most vehicles have twelve volt lights, twelve volt startermotor and twelve volt ancillary motors for such things as windshieldwipers, electric door locks and power windows. The twelve volt systemswork well and twelve volt fractional horsepower motors are ideal forintermittent use as the current draw for these small motors is notgreat. Twelve volt engine starter motors produce very high torque forengine starting, but at a very high current draw, often in the range of400 amps per hour. These motors can only run for a few minutes beforethey drain the vehicle battery bank and/or burn up.

The twelve volt base electrical systems in vehicles have precluded thedevelopment of practical and efficient electrically driven equipment,such as air compressors, hydraulic pumps, air conditioners and vacuumsystems to be mounted on service, recreational, or over the roadvehicles. As an example: If a service truck requires an air compressorfor inflating tires, or running air tools, the compressor is invariablydriven by an internal combustion engine. The engine requires muchmaintenance, is expensive to run and emits pollutants into theatmosphere. Twelve volt DC motors draw far too much current to make sucha compressor a viable portable option for a continuous air supply.

Hydraulic systems for tow trucks and auxiliary hydraulic power take-offsare driven by pumps that the vehicle engine powers, or by auxiliaryinternal combustion engines mounted on the vehicle. Such engine-poweredhydraulic pumps for equipment like hydraulic lifts, or hydraulic chainsaws are lighter, safer and easier to use than their internal combustionengine counterparts. However, an internal combustion engine must berunning all the time and they are loud and dirty and high maintenanceitems.

At any given time, there are 300,000 trucks on the road in the USA.According to the Environmental Protection Agency (EPA), they add 300million tons of Carbon Dioxide to the atmosphere annually. TheDepartment of Transportation (DOT) requires that drivers take a minimumof a 10 hour break every 24 hours. Currently, 90% of “over the road”trucks must idle their engines during brake time to provide airconditioning (A/C) for the sleeper.

There are a few different varieties of mobile A/C's available now, butthey are either diesel powered by adding an auxiliary engine to thetractor, or they are 12 volt battery systems that are limited as to theBTU output because of the high current draw of either “direct DC”motors, or inverters.

SUMMARY

Generally speaking, a vehicle refrigeration system may include a vehiclepower device. The vehicle power device may include a vehicle powersource configured to output a first voltage, a plurality of batteries,each battery configured to provide a second voltage, a plurality ofswitches coupled between the batteries, and a controller coupled to theplurality of switches. The controller may be configured to place theplurality of switches in a first mode of operation so that the pluralityof batteries is coupled in parallel and receives a charge from thevehicle power source, and place the plurality of switches in a secondmode of operation so that the plurality of batteries is coupled inseries and provides a combined voltage greater than the first voltageand the second voltage. The vehicle refrigeration system may include avehicle refrigeration device comprising an evaporator configured toprovide cooling based upon refrigerant fluid, a condenser configured toprocess the refrigerant fluid downstream from the evaporator, and acompressor configured to operate based upon the combined voltage, andtransmit the refrigerant fluid from the evaporator to the condenser.

More specifically, the condenser may comprise first and second condenserunits being spaced apart, and first and second condenser fans beingaligned with each other and both being between the first and secondcondenser units. The compressor may comprise an electrical motorconfigured to operate based upon the combined voltage, and a compressorunit configured to be driven by the electrical motor.

The controller may have has a first input coupled to an output of thevehicle power source, and the controller may be configured to place theplurality of switches in the first mode of operation only when the firstvoltage is greater than or equal to a threshold voltage. The controllermay have a second input coupled to an output of the plurality ofbatteries, and the controller may be configured to place the pluralityof switches in the first mode of operation only when the second voltageis less than the threshold voltage. The controller may have a thirdinput coupled to the compressor, and the controller may be configured toplace the plurality of switches in the first and second modes ofoperation based upon an operational characteristic of the compressor.

Also, the vehicle power device may further comprise a power switchcoupled between the vehicle power source and each battery of theplurality thereof. The controller may be configured to control the powerswitch. The controller may be configured to close the power switch afterthe plurality of switches has entered the first mode of operation. Thecontroller may be configured to open the power switch in the second modeof operation. For example, the vehicle power source may comprise avehicle starter battery, and an alternator coupled thereto.

Another aspect is directed to a method for making a vehiclerefrigeration system. The method may include coupling a vehicle powerdevice comprising a vehicle power source configured to output a firstvoltage, a plurality of batteries, each battery configured to provide asecond voltage, a plurality of switches coupled between the batteries,and a controller coupled to the plurality of switches. The controllermay be configured to place the plurality of switches in a first mode ofoperation so that the plurality of batteries is coupled in parallel andreceives a charge from the vehicle power source, and place the pluralityof switches in a second mode of operation so that the plurality ofbatteries is coupled in series and provides a combined voltage greaterthan the first voltage and the second voltage. The method may includecoupling a vehicle refrigeration device to the vehicle power device. Thevehicle refrigeration device may have an evaporator configured toprovide cooling based upon refrigerant fluid, a condenser configured toprocess the refrigerant fluid downstream from the evaporator, and acompressor configured to operate based upon the combined voltage, andtransmit the refrigerant fluid from the evaporator to the condenser.

Yet another aspect is directed to a method for operating a vehiclerefrigeration system. The method may include operating a vehicle powerdevice by at least operating a vehicle power source to output a firstvoltage, operating a plurality of batteries so that each batteryprovides a second voltage, operating a plurality of switches coupledbetween the batteries, and operating a controller coupled to theplurality of switches. The controller may to place the plurality ofswitches in a first mode of operation so that the plurality of batteriesis coupled in parallel and receives a charge from the vehicle powersource, and place the plurality of switches in a second mode ofoperation so that the plurality of batteries is coupled in series andprovides a combined voltage greater than the first voltage and thesecond voltage. The method may include operating a vehicle refrigerationdevice while coupled to the vehicle power device, the vehiclerefrigeration device comprising an evaporator configured to providecooling based upon refrigerant fluid, a condenser configured to processthe refrigerant fluid downstream from the evaporator, and a compressorconfigured to operate based upon the combined voltage, and transmit therefrigerant fluid from the evaporator to the condenser.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a vehicle power system, according tothe present invention.

FIG. 2 is a schematic diagram of 48 volt example embodiment with theinvention in a parallel mode.

FIG. 3 is a schematic diagram of the 48 volt example embodiment with theinvention in a series mode.

FIG. 4 is a perspective view of a vehicle with the vehicle refrigerationsystem, according to the present invention.

FIG. 5 is a schematic diagram of the vehicle form FIG. 4.

FIG. 6 is a schematic diagram of the vehicle refrigeration device fromthe vehicle of FIG. 4.

FIG. 7A is a perspective view of a portion of the vehicle refrigerationdevice from the vehicle of FIG. 4.

FIG. 7B is a perspective view of the compressor of the vehiclerefrigeration device from the vehicle of FIG. 4.

FIG. 7C is a perspective view of a portion of the compressor of thevehicle refrigeration device from the vehicle of FIG. 4.

FIG. 7D is a perspective view of a portion of the vehicle refrigerationdevice from the vehicle of FIG. 4.

DETAILED DESCRIPTION

The present disclosure will now be described more fully hereinafter withreference to the accompanying drawings, in which several embodiments ofthe invention are shown. This present disclosure may, however, beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein. Rather, these embodiments areprovided so that this disclosure will be thorough and complete, and willfully convey the scope of the present disclosure to those skilled in theart. Like numbers refer to like elements throughout.

The present invention melds twelve volt DC vehicular generating systemswith twenty four, thirty six, or forty eight or any motor voltage evenlydivisible by twelve. The invention may also be used in any vehicle,including but not limited to, automobiles, trucks, commercial trucks,boats, etc.

Generally speaking, a vehicle power system may include a vehicle powersource configured to output a first voltage, and a plurality ofbatteries, each battery configured to provide a second voltage. Thevehicle power system may also include a plurality of switches coupledbetween the batteries, and a controller coupled to the plurality ofswitches. The controller may be configured to place the plurality ofswitches in a first mode of operation so that the plurality of batteriesis coupled in parallel and receives a charge from the vehicle powersource, and place the plurality of switches in a second mode ofoperation so that the plurality of batteries is coupled in series andprovides a combined voltage greater than the first voltage and thesecond voltage, the combined voltage driving a load.

The invention uses a bank of batteries separate from the host vehiclebatteries and charging system to build, in a series mode, theappropriate voltage to run motors at a higher voltage than 12 volts, forexample, two batteries for 24 volts, three batteries for 36 volts, fourbatteries for 48 volts, etc. This separate bank of batteries remainsswitched to a parallel configuration which allows for individual batterycharging from the host 12 volt system. At the moment a demand for ahigher voltage is received, the parallel configuration is turned “off”to isolate each battery. The batteries are then switched, via the use ofmechanical or solid state relays, to a series configuration, thusproviding the higher voltage required to do the work.

This invention supplies electrical power for running motors of a highervoltage requirement than that of the vehicle, or boat base electricalsystem to run compressors or pumps on an intermittent basis.Consequently, equipment normally reliant on an internal combustionengine or an electrical power inverter can be powered by an electricmotor with my invention.

In short, the basis of the present invention is the “Power ManagementModule” and a bank of batteries. The Power Management Moduleautomatically switches the battery bank between a “parallel” state and a“series” state depending on a requirement. Again, to reemphasize, thatalthough a common example of one embodiment of the present inventiondescribed herein and in the accompanying schematics refers to a 48 voltmotor, requiring a bank of four 12 volt batteries, the present inventionmay be applied to any system requiring a bank of batteries equaling 24,36, 48, etc.

By way of example, to run a 48 volt motor with the present inventivesystem, the Power Management Module must configure the battery bank to a“series” configuration to supply 48 volts for the motor. When the motoris finished running, the Power Management Module must re-configure thebattery bank to a “parallel” configuration so that the vehicle 12 voltbattery system can charge the batteries. The Power Management Modulealso embodies several other functions so as to make this systemreliable. These functions will be described later.

An example for which the present invention is particularly useful wouldbe on sailboats of sufficient size to allow for extended cruising.Typically, electric anchor windlasses are powered by 12 volt direct DCmotors, motors that are much the same as starter motors for internalcombustion engines. The problem is that the current draw with a 12 voltDC windlass motor is so high as to require additional batteries to beinstalled in the bow of the boat, near the windlass, a place where extraweight becomes critical for waterline trim. Additionally, sheet andhalyard winches are usually manual crank drum type winches. With thepresent invention, one configuration would be to use a 48 voltalternating current (AC) motor and controller to power a hydraulic pump.

Hydraulic motors could be used to turn winches and a windlass with onlysmall hydraulic lines lead from a central part of the vessel. When awinch was called upon for service, the present invention would switchfour of the house batteries to 48 volt series configuration, and back to12 volt parallel when the work is completed. This would be an idealapplication for the present invention as winch and windlass usage aretypically of a low duty cycle, but critical to maintaining proper sailtrim while underway. To recharge the batteries, it is common to run thesailboat engine at least one hour per day while on a passage to chargethe battery bank. Many systems on board require 12 volt based power,such as running lights, navigation systems and refrigeration.

Another excellent example for the present invention would be a vehiclemounted air compressor. For example, a 6 horsepower (hp), 3-phase, 48volt AC motor with controller would be the appropriate size to turn acompressor that compresses air at the rate of 22 cubic feet per minuteto 175 psi. The compressor stores energy in its reservoir for later use.The motor and pump are designed to run intermittently, a perfectapplication for the present invention.

As described above, the present invention uses a bank of batteriesseparate from the host vehicle batteries and charging system to build,in a series mode, the appropriate voltage to run motors at a highervoltage than 12 volts. Example, two batteries for 24 volts, threebatteries for 36 volts, four batteries for 48 volts, etc. This separatebank of batteries remains switched to a parallel configuration whichallows for individual battery charging from the host 12 volt system. Atthe moment a demand for a higher voltage is received, the parallelconfiguration is turned “Off” to isolate each battery. The batteries arethen switched, via the use of mechanical or solid state relays, to aseries configuration, thus providing the higher voltage required to dothe work.

Typical System Components:

A sufficient number of 12 volt storage batteries that when wired in“series” provide the desired DC voltage (e.g. Two batteries for 24 voltsDC, three batteries for 36 volts DC, 4 Batteries for 48 volts DC, etc.).One master power solenoid, continuous duty with a 12 volt coil capableof switching 200 amps (See Power Relay “K” on drawing FIGS. 1,2 & 3);One programmable controller or micro-processor to control the systemlogic (see Output 1 & Output 2 and output 3 in FIGS. 2 & 3);Load solenoids, continuous duty, for switching between “parallel” and“series” mode. A 48 volts DC system requires ten (10) such solenoidswith 12 volts DC coils and capable of switching 100 amps (See in FIGS. 2& 3: A, B, C, D, E F, G, H, J & L). Note: a 36 volts DC motor requireseight (8) such solenoids and a 24 volts DC system requires six (6) suchsolenoidsFour batteries for a 48 volts DC voltage output, 3 batteries for a 36volts DC voltage output, 2 batteries for a 24 volts DC voltage output(See in FIGS. 2 & 3: batteries, A B, C & D); and Two each Analog PLCInputs (See FIG. 1: I02 & I03) that read 10-20 volts DC.

How the Power Management Module Works:

This invention is reliant on feedback in the form of a start and stopcommand from the equipment to which the Power Management Module ismetering electromotive force.

The example used here is based on a 48 volt system with four 12 voltbatteries. This scenario is based on a vehicle mounted electric 6 hp, 48volt, 3-phase AC motor with a 48 volt motor controller that draws 40amps per hour at 48 volts when running. The air compressor is typical ofa 6 hp compressor that runs on 220 volt AC power, in that it compresses22 cubic feet of air per minute to 175 psi. However in this example, thecompressor is mounted on a service truck that is used to run air toolsand inflate tires. For this explanation we are to consider that thetruck has a 12 volt electrical system with at least a 135 amp-houralternator for battery charging.

Explanation of the Ladder Logic (FIG. 1)

NOTE: Initially, all relays are open, and there is no power to any ofthe relay coils. All relay contacts are in an OPEN state. All batteriesare isolated from one another and from the truck batteries.

1) When the air pressure in the reservoir of the vehicle mounted aircompressor drops to a level that triggers the switch to run thecompressor, 12 volts from the vehicle battery system is switched throughthe pressure switch to the Input on the PLC (See FIG. 1).If Analog Input I03 (See FIG. 1) registers a voltage above 11 volts,thena) All solenoids (see FIG. 3) A, B, C, D, E, F, G, H, J, L & K areswitched off. All batteries are isolated from one another and the truckbattery system.b) One second later, Output 2 from the PLC (See FIG. 3) is turned onwhich in turn energizes relays H, J & L, which in turn configuresbatteries A, B, C & D to a series configuration to provide 48 volts DCto the compressor motor, to run the compressor.

OR:

If Analog Input I03 registers a voltage below 11 volts, then the systemwill not switch to series mode until the Power Management ModuleBatteries register over 12.8 volts, which means the truck engine must berun to increase the truck battery voltage to facilitate charging thePower Management Module Battery Bank.2) When the Compressor Reservoir is charged to its high limit, thecompressor pressure switch will switch to “open contacts”. When thishappens, PLC input contacts no longer have a 12 volt signal;a) Relays H, J, & L drop out, once again isolating all batteries.b) If Analog Input I02 registers a voltage of over 12.8 volts on thevehicle battery, and, if the Power Management Module batteries are of alesser voltage than the vehicle batteries, thena) One second later, PLC Output 1 closes, providing a 12 volt signalvoltage to relays coils A, B, C, D, E, F & G, thereby closing the relaycontacts. (Note; Contacts are closed before current is turned on tothem. Arcing cannot happen as the contacts are already closed.

NOTE: PLC Analog inputs compare the voltage between I02, the vehiclebattery and I03, the Power Management Module batteries. If the PowerManagement Module batteries have a higher voltage than the vehiclebatteries, then the system will not switch to a Parallel state toprevent back charging the vehicle batteries and reducing the effectiverun time of the Power Management Module batteries.

b) One second later, PLC Output 3 closes, providing 12 volt signalvoltage to Power Relay “K”, which in turn closes contacts to provide 12volt power to batteries A, B, C & D to charge.

If the vehicle battery system drops below 12.8 volts as measured by PLCAnalog input 102 (a voltage that insures an ability to start the vehicleengine), then PLC Output 1, will not close to power A, B, C, D, E F & G.and Power Relay K will not engage.

Parallel Mode FIG. 2 If

1) If the vehicle battery voltage is greater than 12.8 volts and2) The Power Management Batteries have a charge less than the vehiclebattery voltage, thena) Relays A, B, C, D, E, F, and G are energized, the relay contactsbecome closed.NOTE: Relays H, J, and L are open as depicted in FIG. 2.b) One second later, Power Relay (K) is energized. This provides powerto charge the Power Management Module batteries A, B, C and D. Asdepicted in FIG. 2, each individual battery Plus side (+) becomesconnected to the Positive side of the truck battery and each negativebattery pole becomes connected to the Negative (chassis) side.c) When the batteries become completely charged, the vehicle alternatorwill adjust itself to provide an appropriate trickle charge.

Series Mode FIG. 3

1) When the PLC receives a 12 volt signal Input from the compressor,indicating a low limit setting, (See PLC Input, FIG. 1)a) The Power Relay (K) is switched off via PLC Output #3.b) One second later relays A, B, C, D, E, F and G are switched off viaPLC Output 1.c) One second later, relays H, J, and L are energized via PLC Output 2.(FIG. 3). This in turn allows current to flow from Battery D− (Chassis)to Battery D+(12 volts) to relay L thru to Battery C−, to Battery C+(24volts), to relay J, thru J to Battery B−, to Battery B+(36 volts), toRelay H, thru H to Battery A−, to A+(48 volts) to 48 volt motorcontroller.

NOTE: There are many types of equipment now available that require 48volts DC voltage that converts power for brushless DC or three phasepower. It is not the purpose of this invention to limit the use of thisinvention to just one type of motor controller, but merely show thathigh amperage 48 volt power can be delivered for intermittent use.

2) When the compressor pressure sensing contacts go open (Reservoirpressure reaches 175 psi), a) PLC INPUT (FIG. 1) drops out, Relays H, J,and L are de-energized and go to OPEN state (FIG. 2)b) When the PLC Input 2 (See FIG. 1) senses that the vehicle chargingsystem has a voltage greater than 12.8 volts and a voltage greater thanthe Power Management Module battery voltage, the system reverts toParallel Charge as described above.

In summary, the Power Management Module interfaces equipment meant tooperate on high voltage equipment, heretofore unable to run on 12 voltvehicular electrical systems. The novel concept that charging can takeplace intermittently while the high voltage motor is not running allowsfor the use of new technology type motors such as the 48 volt, 3-phase,AC motors to do the work relegated to ancillary internal combustionmotors.

Referring now additionally to FIGS. 4-5, a vehicle 10 according to thepresent invention is now described. The vehicle 10 illustrativelyincludes a vehicle refrigeration system 19. The vehicle refrigerationsystem 19 illustratively includes a vehicle power device 11. As will beappreciated, the vehicle power device 11 is similarly constituted to thevehicle power system described in FIGS. 1-3.

In the illustrated embodiment, the vehicle 10 comprises a semi-trailertruck, and the vehicle refrigeration system 19 is purposed to providerefrigeration to the passenger compartment of the vehicle, i.e. coolingfunction of a climate control system. Of course, the vehiclerefrigeration system 19 can be installed in other vehicle types, and thevehicle refrigeration system 19 may be used to provide refrigeration tothe cargo compartment of the semi-trailer truck, i.e. a refrigeratortruck.

In this embodiment, the vehicle refrigeration system 19 includes avehicle refrigeration device 12 comprising an evaporator 13 configuredto provide cooling based upon refrigerant fluid, a condenser 14configured to process the refrigerant fluid downstream from theevaporator, and a compressor 15 configured to operate based upon thecombined voltage, and transmit the refrigerant fluid from the evaporatorto the condenser.

As perhaps best in FIG. 4, the vehicle refrigeration device 12illustratively includes an outdoor module 16 carrying the compressor 15and the condenser 14. Given that the condenser and compressor releaselarge amounts of thermal energy (i.e. radiated heat), they are desirablystationed on the exterior of the vehicle 10 where they wouldn't hamperrefrigeration efforts. Helpfully, the outdoor module 16 is flexible andself-contained, and permits installation throughout the vehicle 10. Inother words, the rearward cab installation in the illustrated embodimentis merely exemplary, and the outdoor module 16 could also be installedelsewhere, such as adjacent the fuel tank under the fuel tank sidefairings.

The outdoor module 16 includes an outer housing for carrying theinternal components. The outer housing is perforated to permitsufficient air flow for the components therein. Also, the outdoor module16 includes first and second valve connections for coupling refrigeranthoses thereto. The refrigerant hoses are routed to the evaporator 13.

Referring now additionally to FIGS. 6-7C, the vehicle refrigerationdevice 12 illustratively includes the compressor 15 having an electricalmotor 27 configured to operate based upon the combined voltage (e.g.40-60 volts), and a compressor unit 28 configured to be driven by theelectrical motor via a belt 30. The compressor forces the refrigerantfluid into the condenser 14. The condenser 14 illustratively includesfirst and second condenser units 20 a-20 b being spaced apart, and firstand second condenser fans 18 a-18 b being aligned with each other andboth being between the first and second condenser units. As perhaps bestseen in FIG. 7C, the condenser 14 includes first and second rails 26a-26 b for mounting the first and second condenser fans 18 a-18 bbetween the first and second condenser units 20 a-20 b.

The vehicle refrigeration device 12 illustratively includes an inlinefilter 22 downstream from the condenser 14. Once the condenser 14reverts the refrigerant fluid into the liquid state, the refrigerantfluid is processed through the inline filter 22. The vehiclerefrigeration device 12 illustratively includes an evaporator 13downstream from the inline filter 22. The evaporator 13 illustrativelyincludes an evaporator coil 17. As will be appreciated, the liquid staterefrigerant fluid is passed through the evaporator coil 17 and removesthermal energy from the ambient air, and then converts the refrigerantfluid into the gas state. Although not depicted, the evaporator 13 mayinclude a fan to force air over fins of the evaporator coil 17. Thevehicle refrigeration device 12 illustratively includes an accumulator21 between the evaporator 13 and the compressor 15 and configured totrap moisture and debris in the refrigerant fluid.

As perhaps best seen in FIGS. 7A and 7D, the outdoor module 16 is shownwith the outer housing removed. The outdoor module 16 illustrativelyincludes a frame 25. The first and second condenser units 20 a-20 b, andthe first and second condenser fans 18 a-18 b are carried by the frame25. The outdoor module 16 illustratively includes a dryer unit 23, and acontroller 24 also carried by the frame 25. In FIG. 7D, the frame 25 isremoved along with the outer housing, and a subframe 31 is shown. Theoutdoor module 16 illustratively includes a dryer pressure switch 33coupled to the dryer unit 23, and a plurality of feet 32 a-32 c coupledto the subframe 31 for coupling the subframe to the frame 25.

Another aspect is directed to a method for making a vehiclerefrigeration system 19. The method includes coupling a vehicle powerdevice 11 comprising a vehicle power source configured to output a firstvoltage, a plurality of batteries, each battery configured to provide asecond voltage, a plurality of switches coupled between the batteries,and a controller coupled to the plurality of switches. The controller isconfigured to place the plurality of switches in a first mode ofoperation so that the plurality of batteries is coupled in parallel andreceives a charge from the vehicle power source, and place the pluralityof switches in a second mode of operation so that the plurality ofbatteries is coupled in series and provides a combined voltage greaterthan the first voltage and the second voltage. The method includescoupling a vehicle refrigeration device 12 to the vehicle power device11. The vehicle refrigeration device 12 includes an evaporator 13configured to provide cooling based upon refrigerant fluid, a condenser14 configured to process the refrigerant fluid downstream from theevaporator, and a compressor 15 configured to operate based upon thecombined voltage, and transmit the refrigerant fluid from the evaporatorto the condenser.

Yet another aspect is directed to a method for operating a vehiclerefrigeration system 19. The method includes operating a vehicle powerdevice 11 by at least operating a vehicle power source to output a firstvoltage, operating a plurality of batteries so that each batteryprovides a second voltage, operating a plurality of switches coupledbetween the batteries, and operating a controller coupled to theplurality of switches. The controller places the plurality of switchesin a first mode of operation so that the plurality of batteries iscoupled in parallel and receives a charge from the vehicle power source,and place the plurality of switches in a second mode of operation sothat the plurality of batteries is coupled in series and provides acombined voltage greater than the first voltage and the second voltage.The method includes operating a vehicle refrigeration device 12 whilecoupled to the vehicle power device, the vehicle refrigeration device 12comprising an evaporator 13 configured to provide cooling based uponrefrigerant fluid, a condenser 14 configured to process the refrigerantfluid downstream from the evaporator, and a compressor 15 configured tooperate based upon the combined voltage, and transmit the refrigerantfluid from the evaporator to the condenser.

Advantageously, the vehicle refrigeration system 19 may develop twicethe BTU output of typical system available owing to several factors.Firstly, the vehicle refrigeration system 19 may employ a 6 hp, 48 volt,3 phase AC motor to drive a 3 ton compressor. In fact, only 2 hp is usedto produce 24,000 BTU's of refrigeration. Secondly, in the vehiclerefrigeration system 19, cold air generation is such that the compressor15 only runs 25-33% of the time, i.e. providing a reduced duty cycle.Most typical systems may run close to 100% of the time to produce enoughcold air to cool the sleeper, or refrigerate the cargo hold. Thisprovides for reduced maintenance and wear and tear in the vehiclerefrigeration system 19.

In an example embodiment of the vehicle refrigeration system 19, thecurrent draw is: (resistance 2 hp) 1,500w+48v×0.33 (time, per hour)=10.3amps per hour. Helpfully, there are two condenser fan 18 a-18 bs used tocarry the heat away from first and second condenser units 20 a-20 b.Each condenser fan 18 a-18 b produces 660 cfm of air flow. In theexemplary embodiment (i.e. the outdoor module 16), by placing the firstcondenser unit 20 a on the intake side and second condenser unit 20 b onthe output side, there is an increase in efficiency of about 15% overthe typical side-by-side arrangement.

For example, each of the first and second condenser fans 18 a-18 bcomprise a brushless 48 volt DC motors that draws only 0.58 amps each.This is significant because typical electric systems have to use 12 voltfans that draw about 16 amps of current. Advantageously, the vehiclerefrigeration system 19 may be substantially more power efficient.

The air handler fan (i.e. the fan associated with the evaporator 13) isalso a brushless DC, 48 volt fan that only draws 0.58 amps. The vehiclerefrigeration system 19 may employ two conventions that add up to about8% free cooling. In particular, the compressor 15 may have (in contrastto most typical approaches) no restriction on “short cycling” thecompressor.

Therefore, when the evaporator 13 temperature drops to about 28° F., thecompressor 15 shuts off, but the air handler motor continues to blow airacross the chilled evaporator 13 until the evaporator temp increases toabout 40° F., at which time the compressor restarts if the thermostatset point (i.e. the desired target temperature) has not been reached.When the thermostat set point has been reached, the compressor 15 turnsoff, but the air handler motor continues to blow air across the chilledevaporator 13 for about 90 seconds.

In an exemplary embodiment of the vehicle refrigeration system 19, eachof the plurality of batteries comprise a 48 volt, 110 amp, lithium ironPoshate4 (LiFePo4) battery, which weighs 135 pounds. This is in contrastto typical approaches that use 12/24 volt based batteries.

Moreover, charging the 48 volt battery from a 12 volt supply is anotherfeature of the vehicle refrigeration system 19. The vehiclerefrigeration system 19 may not deep cycle any of the batteries. Duringoperation, the vehicle refrigeration system 19 may use electrical poweravailable from the battery between the voltages of fully charges 53.8volts, down to 44 volts, at which time the compressor 15 will no longerrun until a charge is applied to the battery. Helpfully, the vehiclerefrigeration system 19 may avoid deep cycling a battery, which maydramatically shorten the life of a battery.

As will be appreciated by those skilled in the art, the department oftransportation (DOT) allows for a free 400 pounds gross weight for anair conditioner. In an exemplary embodiment of the vehicle refrigerationsystem 19, the total weight is less than 350 pounds. Most typicalapproach units are around 500 pounds. Indeed, in typical approaches, 4batteries alone (e.g. 12 volt AGM variety) weigh 300 pounds.

Many modifications and other embodiments of the present disclosure willcome to the mind of one skilled in the art having the benefit of theteachings presented in the foregoing descriptions and the associateddrawings. Therefore, it is understood that the present disclosure is notto be limited to the specific embodiments disclosed, and thatmodifications and embodiments are intended to be included within thescope of the appended claims.

1. A vehicle refrigeration system comprising: a vehicle power devicecomprising a vehicle power source configured to output a first voltage,a plurality of batteries, each battery configured to provide a secondvoltage, a plurality of switches coupled between said batteries, and acontroller coupled to said plurality of switches and configured to placesaid plurality of switches in a first mode of operation so that saidplurality of batteries is coupled in parallel and receives a charge fromsaid vehicle power source, and place said plurality of switches in asecond mode of operation so that said plurality of batteries is coupledin series and provides a combined voltage greater than the first voltageand the second voltage; and a vehicle refrigeration device comprising anevaporator configured to provide cooling based upon refrigerant fluid, acondenser configured to process the refrigerant fluid downstream fromsaid evaporator, and a compressor configured to operate based upon thecombined voltage, and transmit the refrigerant fluid from saidevaporator to said condenser.
 2. The vehicle refrigeration system ofclaim 1 wherein said condenser comprises: first and second condenserunits being spaced apart; and first and second condenser fans beingaligned with each other and both being between said first and secondcondenser units.
 3. The vehicle refrigeration system of claim 1 whereinsaid compressor comprises an electrical motor configured to operatebased upon the combined voltage, and a compressor unit configured to bedriven by said electrical motor.
 4. The vehicle refrigeration system ofclaim 1 wherein said controller has a first input coupled to an outputof said vehicle power source; and wherein said controller is configuredto place said plurality of switches in the first mode of operation onlywhen the first voltage is greater than or equal to a threshold voltage.5. The vehicle refrigeration system of claim 4 wherein said controllerhas a second input coupled to an output of said plurality of batteries;and wherein said controller is configured to place said plurality ofswitches in the first mode of operation only when the second voltage isless than the threshold voltage.
 6. The vehicle refrigeration system ofclaim 1 wherein said controller has a third input coupled to saidcompressor; and wherein said controller is configured to place saidplurality of switches in the first and second modes of operation basedupon an operational characteristic of said compressor.
 7. The vehiclerefrigeration system of claim 1 wherein said vehicle power devicefurther comprises a power switch coupled between the vehicle powersource and each battery of said plurality thereof.
 8. The vehiclerefrigeration system of claim 7 wherein said controller is configured tocontrol said power switch.
 9. The vehicle refrigeration system of claim7 wherein said controller is configured to close said power switch aftersaid plurality of switches has entered the first mode of operation. 10.The vehicle refrigeration system of claim 7 wherein said controller isconfigured to open said power switch in the second mode of operation.11. The vehicle refrigeration system of claim 1 wherein said vehiclepower source comprises a vehicle starter battery, and an alternatorcoupled thereto.
 12. A method for making a vehicle refrigeration system,the method comprising: coupling a vehicle power device comprising avehicle power source configured to output a first voltage, a pluralityof batteries, each battery configured to provide a second voltage, aplurality of switches coupled between the batteries, and a controllercoupled to the plurality of switches and configured to place theplurality of switches in a first mode of operation so that the pluralityof batteries is coupled in parallel and receives a charge from thevehicle power source, and place the plurality of switches in a secondmode of operation so that the plurality of batteries is coupled inseries and provides a combined voltage greater than the first voltageand the second voltage; and coupling a vehicle refrigeration device tothe vehicle power device, the vehicle refrigeration device comprising anevaporator configured to provide cooling based upon refrigerant fluid, acondenser configured to process the refrigerant fluid downstream fromthe evaporator, and a compressor configured to operate based upon thecombined voltage, and transmit the refrigerant fluid from the evaporatorto the condenser.
 13. The method of claim 12 wherein the condensercomprises: first and second condenser units being spaced apart; andfirst and second condenser fans being aligned with each other and bothbeing between the first and second condenser units.
 14. The method ofclaim 12 wherein the compressor comprises an electrical motor configuredto operate based upon the combined voltage, and a compressor unitconfigured to be driven by the electrical motor.
 15. The method of claim12 wherein the controller has a first input coupled to an output of thevehicle power source; and wherein the controller is configured to placethe plurality of switches in the first mode of operation only when thefirst voltage is greater than or equal to a threshold voltage.
 16. Themethod of claim 15 wherein the controller has a second input coupled toan output of the plurality of batteries; and wherein the controller isconfigured to place the plurality of switches in the first mode ofoperation only when the second voltage is less than the thresholdvoltage.
 17. A method for operating a vehicle refrigeration system, themethod comprising: operating a vehicle power device by at leastoperating a vehicle power source to output a first voltage, operating aplurality of batteries so that each battery provides a second voltage,operating a plurality of switches coupled between the batteries, andoperating a controller coupled to the plurality of switches and to placethe plurality of switches in a first mode of operation so that theplurality of batteries is coupled in parallel and receives a charge fromthe vehicle power source, and place the plurality of switches in asecond mode of operation so that the plurality of batteries is coupledin series and provides a combined voltage greater than the first voltageand the second voltage; and operating a vehicle refrigeration devicewhile coupled to the vehicle power device, the vehicle refrigerationdevice comprising an evaporator configured to provide cooling based uponrefrigerant fluid, a condenser configured to process the refrigerantfluid downstream from the evaporator, and a compressor configured tooperate based upon the combined voltage, and transmit the refrigerantfluid from the evaporator to the condenser.
 18. The method of claim 17wherein the condenser comprises: first and second condenser units beingspaced apart; and first and second condenser fans being aligned witheach other and both being between the first and second condenser units.19. The method of claim 17 wherein the compressor comprises anelectrical motor configured to operate based upon the combined voltage,and a compressor unit configured to be driven by the electrical motor.20. The method of claim 17 wherein the controller has a first inputcoupled to an output of the vehicle power source; and wherein thecontroller is configured to place the plurality of switches in the firstmode of operation only when the first voltage is greater than or equalto a threshold voltage.